Test hole device



June 8, 1937.

4. c. DUCOMMUN TEST HOLE DEVICE Filed Dec. 31, 1955 2 Sheets-Sheet lINVENTOR Jesse Cflucommun ATTORNEY June 8, 1937. J. c. DUCOMMUN TESTHOLE DEVICE Filed Dec. 31, 1935 2 Sheets-Sheet 2 A! I I w INVENTOR JesseCDacommun Patented June 8, 1937 UNITED STATES PATENT OFFICE TEST HOLEDEVICE Jesse C. Ducommun', Hammond, Ind., assignor to Standard OilCompany, Chicago, 11]., a corporation of Indiana This invention relatesto a test hole device or. in other words, to a device to permit themeasurement of the thickness of the wall of an article such as apressure vessel, reaction chamber, fractionating chamber, pipe line,etc.

Articles of the types mentioned are frequently subjected to corrosion,erosion and other forces tending to reduce the wall thickness. Ittherefore becomes necessary, particularly in the case of vessels andlines subjected to pressure, to measure the wall thickness from time totime in order to determine whether or not the article is in safecondition for further use. This is especially important in the case ofoil refinery equipment in order to minimize fire and explosion hazards.

The testing of wall thickness is conducted while the article in questionis temporarily out of service, which normally occurs from time to time.In the case of metal oil refinery equipment, the usual method has beento drill a hole through the wall of the article, insert a pair ofcalipers through the hole, measure the wall thickness, tap the hole,screw a plug into the tapped hole, cut the plug off flush with the holeand weld it in place. This is a time-consuming operation. Moreover itnecessitates that the next test hole be drilled at another location andit is therefore impossible to check the wall thickness atthe same pointafter further operation. Since the point originally chosen is usuallythat at which maximum corrosion or erosion is expected, this is highlyundesirable.

Furthermore, the prior method which involves welding a plug in placecannot be used in the case of certain structural materials, such forinstance, as alloy steels of the type containing about 4% to 6%chromium-and usually about 0.5% molybdenum. When welded and allowed tocool. these alloy steels air, harden and become brittle. It: istherefore necessary to heat treat them to restore the desired propertiesand this cannot be done without dismantling the equipment and taking itback to the shops. Furthermore, there are some structural materialswhich cannot be welded at all.

It-is an object of my invention to overcome the aforementioned and otherdifficulties of the prior art by providing a test hole device by meansof which the thickness of a wall can be repeatedly measured at the samepoint. Another object of my invention is to provide a test hole devicethe use of which does not involve any welding operation once the deviceis installed. A further object of my invention is to provide a test holedevice which facilitates operation. Other and more detailed objects ofthe: testing my invention will become apparent asthe de- 5 scriptionthereof proceeds.

Certain preferred embodiments of my invention will now be described inconnection with the accompanying drawings which illustrate certainpreferred embodiments thereof. These drawings form a part of thisspecification.

In the drawings: Figure 1 is an elevation partly in section showing atest hole device in accordance with my invention;

Figure. 2.15 a plan view corresponding to Fig: ure 1; v

Figure 3 is a detail sectional elevationof the plug used in the testhole device of Figure 1;

li'i

Figure 4 is an elevation partly in section showing the method ofremoving the plug used in the device of Figure l;

Figure 5 is a partial plan view corresponding to Figure 4;

Figure 6 is an elevation ing another form of test ance with myinvention;

Figure 7 is a plan view corresponding to Figure 6;

Figure 8 is an elevation partly in section show;-' ing a preferredmethod of drilling the test hole; and Figure 9 is a partial pianviewcorresponding to Figure 8.

In the drawings like partly in section showcorresponding parts. 1Referring more particularly to Figures 1 to 5,

it will be seen that wall ll of an article of the type mentioned isprovided with a hole l2. The top of the hole H has a bevelled surfacel3. Anannular member H] which may suitably be a pipe nipple surroundshole [2 but is spaced therefrom. Annular member I4 is fastened to orintegral with wall il. As shown, it is welded to wall it by means of acircumferential weld IS.

A removable bonnet or cover cap I6 is attached to annular member M. Thetwo together constitute a plug holder. Bonnet it carries a threadedcentral aperture adapted to receive a stem l'l. As shown stem I1 is anordinary square headed bolt provided with threads i8 which cooperatewith the threads in bonnet l6.

Hole l 2 is plugged by removable plug I9 which is provided with abevelled elled surface'forms a seat with bevel l3 of wall. ll. Plug I9is also provided with a portion 2| which fits tightly into hole l2. Stemii is adap hole device in accord- Y numerals indicate like or k portion20. This bevplace as shown. I Annular member I4 can be welded in placeat the time the article is originally fabricated and 5 can be subjectedto the normal final heat treatment along with the article so that nofield weld- -ing is necessary.

The thickness of wall II is determined when the article is not in use byloosening stem I I,

1 removing bonnet I6 and plug I9 and inserting a corrosion. The bottomof part 2I should preferwall II.

Plug- I9 is preferably provided with a centrally tapped hole 22 oflesser diameter than the diameter ,of' the lower portion of stem I'I.Thus the removal of plug I9 can be accomplished as shown in Figure 4 bymeans of bolt 23. One convenient method of accomplishing this withdrawalis to use a fiat strip or bridge 24 laid across the top of annularmember I4. This strip is provided with a central aperture through whichbolt 23 is inserted. Nut 25 is screwed down into contact with bridge 24and plug I9 can then be lifted by rotating bolt 23. Instead'of using abridge 24, bonnet Iii-can be used for this purpose but in this case nut25 must be larger than the central aperture in bonnet I6.

Another modification of my device is shown in Figures 6 and 7. In thiscase wall II is shown as curved rather than fiat and this necessitatesnotching or otherwise shaping the lower part of annular member I4 toprovide at least a rough fit with wall II.

As-shown in Figure 6, bonnet I 8 instead of being external to annularmember I4 is internal. Also in this modification stem I1 and plug I9 areintegrally connected to form a single piece although still serving thefunction of the separate elements shown in Figure 1. In the device ofFigure 6, bonnet I6 is provided with a bevelled surface 26 at its lowerpart and this cooperates with a corresponding bevelled surface on plugI9. This tends to hold plug I9 in place and in this modification stem I!could be dispensed with. However, it is desirable to use stem I1, asshown, in order to give additional rigidity. In the device illustratedin Figure 6 threads I8 of stem I! cooperate with a nut 21 which isscrewed down in contact with bonnet I6. In either the device of Figure 1or the device of Figure 6 it is, of course, necessary to have hole I2centrally spaced with respect to annular member l4 and the best way toaccomplish this is to ably be cut off flush with the lower surface ofdrill hole I2 after annular member I4 is welded in place. One highlysatisfactory method of accomplishing this is shown in Figures 8 and 9 inwhich a jig 28 is inserted in annular member I4. As shown, jig 28 isprovided with an upper fiattened portion 29 which is used in screwing itinto position. Jig 28 is also preferably provided with a hardened steelbushing 30 surrounding a central aperture 3| through which drill 32 isinserted. Jig 28 thus serves to guide drill 32 and to insure centralplacing of the hole I2. After hole I2 has 75 been drilled and bevel I3has been. formed, he

ed to exert pressure on plug I9 and hold it in test hole device isassembled as shown in Figure 6 or Figure 1.

It will be understood that instead of using difierent structures forbonnet I6 and jig 28, a single structure can be used for both purposes.

While I have described my invention in con nection with certain specificembodiments thereof, it is tobe understood that I am not limited therebybut only to the subject matter of the appended claims which should beconstrued as broadly as the prior art will permit.

I claim:

1. A test hole device for an article having a wall with a hole thereinwhich comprises an annular member surrounding said hole but spacedtherefrom, a removable plug to fit said hole, a .stem for said plug andremovable means cooperating with said annular member and with said stemfor holding said plug in position in said hole.

2. A test hole device for an article having a wall with a hole thereinwhich comprises an annular member surrounding said hole but spacedtherefrom and attached to said wall, a removable plug to fit said hole,a stem for said plug and a removable bonnet cooperating with saidannular member and with said stem to hold said plug in position in saidhole.

3. A test hole device for a metal article having a wall with a holetherein which comprises a pipe nipple welded to said wall surroundingsaid hole but spaced therefrom, a removable plug to fit said hole, saidplug having a bevelled seat cooperating with a bevelled portion of saidwall at the top of said hole, a stem for said plug and a removablebonnet cooperating with said pipe nipple and with said stem to form arigid assembly when said plug is in place.

4. A test hole device for a metal article having a wall with a holetherein which comprises a threaded pipe nipple welded to said wall andsurrounding said hole but spaced therefrom, a plug to fit said hole, abonnet having threads cooperating with the threads on said nipple, saidbonnet serving to hold said plug in position in said hole.

5. A test hole device for a metal article having a wall with a holetherein which comprises a threaded pipe nipple welded to said wall andsurrounding said hole but spaced therefrom, a plug to fit said hole,said plug having a bevelled seat cooperating with a bevelled portion ofsaid wall at the top of said hole, a bonnet having threads cooperatingwith the threads on said nipple and adapted to hold said plug inposition in said hole, a stem attached to said plug and projectingthrough said bonnet, said stem being threaded over a portion of itslength and a nut cooperating with said threads and with said bonnet tohold said stem in place.

6. A test hole device for a metal article having a wall with a holetherein which comprises a threaded pipe nipple welded to said wallsurrounding said hole but spaced therefrom; a plug having a portion to.fit said hole and a bevelled seat .to cooperate with a bevelled portionof said wall at the top of said hole, a threaded cover cap to fit saidthreaded nipple, said cover cap being centrally threaded, and a threadedstem to fit said centrally threaded cover cap,said stem cooperating withsaid cover cap to hold said plug in position in said hole.

'7. A test' hole device according to claim 6 in which the topof saidplug is'tapped to receive means for removing said plug from said hole.

8. A test hole device for an article having a wall with a hole thereinwhich comprises a plug holder at leastp'art of which-ls attached to saida wall in the vicinity of said hole, a removable plug to fit said hole,a stem for said plug, and means carried by said plug holder and by saidstem for to fit saidhole, a stem for said'plug, said plug holder andsaid stem being equipped with corresponding screw threads whereby saidplug can be held in position in said hole or removed therefrom.

10. A test wall with a hole therein which comprises a member attached tosaid wall. in the vicinity of said hole but spaced therefrom, aremovable plug to fit said hole, a stem' for said plug and removablemeans cooperating with said member andwith said stem for holding hole. p

' JESSEC. DUCOMMUN.

hole device for an article having a 7 said plug'in position in said 10

